On May 3, there were more than 65,000 deaths nationally. But the researchers at Columbia’s Mailman School of Public Health found that 61% of infections and 55% of deaths — roughly 36,000 deaths at that point — could have been prevented if the entire country had entered lockdown about a week earlier than it did.

And if those lockdowns had been introduced at the beginning of March, the researchers estimated that there would have been 11,253 deaths — just 17% of the actual total. “A longer response time results in a stronger rebound of infections and death,” the researchers wrote.

In New York state, there would have been fewer than 3,000 deaths if social distancing had begun a week earlier, rather than the 17,581 that there were on May 3, researchers estimated.

“It’s a big, big difference,” Columbia epidemiologist and research team leader Jeffrey Shaman told the New York Times. “That small moment in time, catching it in that growth phase, is incredibly critical in reducing the number of deaths.”

In reality, New York has been the global epicenter of the coronavirus pandemic. The state has seen more than 354,000 cases and 28,636 deaths, according to STAT’s COVID-19 tracker, which have been largely concentrated in New York City and the surrounding areas. The U.S. has seen more than 1.5 million cases nationally and is expected to hit 100,000 deaths by the end of the month.

The study further warned against loosening restrictions too early, finding that the “majority of the US population in several metropolitan areas remains susceptible to COVID-19,” and that a loosening of restrictions would be “more safely affected” in areas where the number of daily confirmed cases are low and there’s an abundance of testing and contract tracing.